nthinuf

Depends on your freeway usage, but I would suggest that you gear for the 35's and live with high rpm's until you get them. As expensive as this is, you don't want to do it twice.


Go outside and measure your tires, then open the FAQs and look in the drivetrain area.


X2 ! Gear for the tires you are going to end up with. 4.56 if you stay with 33's, 4.88 if you plan on moving to 35's.


Cross country at 5k rpm, I could see some wear and tear. Normal driving at 3k rpm, you're fine. Worse mpg's than running at 2500 rpm, but no worries.



I am assuming you have an Auto?? Your transmission gearing is totally different than the OP's 6speed. He would be more than a bit pissed off with you for taking the 5.38 advice.

jeepjackal

no,no i have a 6speed,, ill never drive an auto in a wrangler,, i thinks its better to have a stick when taking it off road. i want that control

nthinuf

5.38's would be over 3300 rpm at 70 with his current tires, and over 3100 rpm with 35's.

4.88's would be about 3k with his current tires, a bit over 2800 with the 35's

4.56's would be around 2800 and 2650.



4.56 would be the better choice for 33's
4.88 might be the better choice for 33's and moving to 35's.
But 5.38's would be a poor ratio for either of his tire choices.

itsajeepthing91

Thank you for all the useful info!

itsajeepthing91

According to the gear chart wouldn't 4.56 be closer to stock with 35s?

nthinuf

Yep. But as noted further up in the thread, 4.56's were very, very hard to find for several years. Assuming they are available now, they would get a manual with 35's back to 'stock' gearing. Since a lot of people consider stock gearing to actually be under-geared, 4.88's are very popular. And for those with 35's that do less higher speed freeway driving, 5.13's are popular. Just depends on your viewpoint and how/where you drive.

Mark Doiron

My stock was 4.10s with 29s, so not in my case.

itsajeepthing91

I am all for getting more power but I do not like sacrificing reliability in order to do so. So with that said there is roughly a 200 rpm difference between 4.56s and 4.88s. The faster things are spinning the more wear that is taking place so from a reliability stand point wouldn't 4.56s be a better option because I would be gaining a slightly bigger pinion gear and decreasing wear with slightly less rev. Sorry for so many questions but this is a big investment for me as my funds are limited and I want to make I do it right the first time.

Olean NY Jeeper

IMO thr Jks engine is happier at 3000 rpms than 2000 rpms. I run 65 on the highway and I am at around 2700-2800 RPMS on the highway. Perfect imo. This is with 34s I think u will be disapointed in 4.56 espec if you go to 35s but its ur jeep.

nthinuf

There is no right or wrong answer. Just 'better' choices for each person and their specific needs.

As far as reliability goes, it's all about the install and the usage.
- If your gear guy does his job right, the wear and tear difference between the two sets will be minimal, bordering on negligible.
- If you get on the gas and bounce through rock fields, you are going to destroy whatever gears you get, using whatever axle you choose. Drive like you know you have weak factory axles, and it shouldn't be an issue with either gearset.